Reciprocating saw

ABSTRACT

A reciprocating saw having a holding frame and detachably inserted therein a separate tension frame equipped with sawblades and supported in the holding frame in a fixed position by straightening means. With the machine there are associated preferably at least two tension frames, which at will may be inserted in the machine and prepared apart from the same for later use therein, respectively.

United States Patent Stautfer 51 July 25, 1972 [54] RECIPROCATING SAW3,362,392 1/1968 Miller ..l25/l7 [72] Inventor: Alfred Stauffer,Steffisburg, Switzerland FOREIGN PATENTS OR APPLICATIONS [731 A ign e: Mh n nf Meyer & B rg 9,416 0/0000 Germany ..143/156 Bern, Switzerland[22] Filed: 10 1970 Primary Examiner-Harold D. Whitehead Appl. No.:62,521

Int. Cl ..B28d 1/02 Field ofSearch ..l25/l2, l6, l7; 143/156 ReferencesCited UNITED STATES PATENTS 3/1963 Hunt ..l25/l7 Attorney-Imirie andSmiley 5 7] ABSTRACT A reciprocating saw having a holding frame anddetachably inserted therein a separate tension frame equipped with sawblades and supported in the holding frame in a fixed position bystraightening means. With the machine there are associated preferably atleast two tension frames, which at will may be inserted in the machineand prepared apart from the same for later use therein, respectively.

10 Claims, 6 Drawing Figures Patented July 25, 1972 3,678,918

v3 Sheets-Sheet 2 INVENTOR ALFRED TAUFFER M HSWL Aetvs.

RECIPROCATING SAW BACKGROUND OF THE INVENTION The present inventionrelates to a reciprocating saw having saw-blades fixed between oppositeyokes of a frame. Such reciprocating saws serve e.g. for sawing quartzcrystals into thin quartz flats for manufacturing oscillator quartzes.For this purpose there must be provided a relatively great number ofsaw-blades nearly juxtaposed. In order to make the best of the materialthe saw-blades should be made thin, which on the other hand requires avery constant strong tension if it is intended to obtain exact planecuts. Therefore, the frame must generate and receive, respectively,tensions of totally many tons, which involves some difficulties in knownreciprocating saws.

In known reciprocating saws there is provided only a single framemovable to and fro within guides and simultaneously serving forstretching the saw-blades. Therefore, it is necessary to supply theframe with stretching means permitting tHe generation of tension forcesin the range of many tons. These tension forces must be generated bybolts or the like when the frame is within the machine; that iscomplicated and time-consuming. The replacement of a worn out saw-bladeset by new one and the stretching of new saw-blade sets also take placewhen the frame remains within the machine. Due to the very high tensionforces the frame is minimally deformated, which involves difficulties inthe guidance and at least inaccuracy. In particular, it is impossible toadjust the saw-blades exactly parallel to the direction of movement ofthe frame being distorted and inexactly guided in case, which, however,is absolutely necessary for an accurate and exact machining.

SUMMARY OF THE INVENTION It is an object of the present invention toeliminate the above mentioned disadvantages of known machines.

The reciprocating saw according to the invention is characterized inthat a separate tension frame bearing the saw-blades is detachablyinserted with lateral clearance in a holding frame movable to and froalong guides and is supported in the holding frame in a fixed positionby straightening means.

The use of a separate tension frame detachably inserted in a guidingframe of the reciprocating saw renders it possible to insert sets ofsawing-blades in the tension frame removed from the machine; therebythis manipulation is considerably facilitated by the possibility ofusing suitable auxiliary implements. First of all it is possible toprovide at least two tension frames for each one machine, so that alwaysone tension frame already equipped with saw-blades may be kept on handand after attrition of a set of saw-blades may be inserted in theholding frames within a very short time. Thus, the time necessary forsetting the reciprocating saw may be shortened considerably.

Since the tension forces ar received exclusively by the tension framepractically no forces and deformations take efiect in the actual holdingframe serving also for guidance. Thus, a sure guidance is guaranteed.Finally, it is very simple in the holding frame to set right accuratelythe tension frame bearing the saw-blades and thereby to adjust exactlythe saw-blades parallel to the direction of movement.

BRIEF DESCRIPTION OF THE DRAWINGS Hereafter the invention is illustratedmore detailed by way of an embodiment shown in the drawings, wherein:

FIG. I is a plan view of the reciprocating saw,

FIG. 2 is a plan view of the holding frame and the tension frameinserted therein, partially in section and on a larger scale,

FIG. 3 is a sectional view taken on the line IIIIII of FIG. 2,

FIG. 4 is a sectional view taken on the line IV-IV of FIG. 2,

FIG. 5 shows a longitudinal section of a hydraulic tension cylinder, and

FIG. 6 is a sectional view taken on the line VIVI of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reciprocating sawschematically shown in FIG. I in total plan view has two parallellongitudinal guides I and 2, along which a holding frame 3 is movable.As FIG. 4 shows, the holding frame 3 has a prismatic guide 4 and an evenguide surface 5. By means of a bolt 6 the holding frame 3 is pivotallyconnected to a driving chariot 7 which is movable to and fro in parallelwith the longitudinal guides I and 2 by means of a crank drive 8, 9. Thedriving chariot 7 has the aim to avoid the transmission of transversecomponents of the driving power of the crank drive directly to theholding frame 3 and thus to avoid any lateral load of this frame.

In a manner later to be described in the holding frame 3 there isinserted a tension frame 10 consisting of two lateral pressure legs 11and a yoke 12 and I3, respectively, at a time. Between the yokes I2 andI3 there are fixed the saw-blades 14 shown in FIG. 1 only partially.Beneath the saw-blades there is provided a table I5 movable up and downhydraulically and on which according to the shown embodiment threequartz crystals 16 are clamped in order to be sawn into flats. Aswinging pipe I7 serves for the feed of grinding materials to thesawblades and the quartz crystals 16, respectively.

FIGS. 2, 3, and 4 show further details of the construction of holdingframe 3 and tension frame 10. The yoke I2 of the tension frame is builtup of a yoke bar 18 and two holding profiles surrounding the same. Theouter legs of the holding profiles 19 and 20 grasp behind shoulders ofthe bar 18 free from play, whilst on the inside between the bar and theinwards projecting legs of the holding profiles l9 and 20 a cavity 21remains. Into this cavity the saw-blades 14 project and there they arefixed by means of holding flats 22 which simultaneously serve forholding fixed the saw-blades to the holding profiles l9 and 20 and forfixing the distance between adjacent saw-blades. A swivelling pivot 23bolted with the holding frame 3 serves for suspension of the yoke 12 ofthe tension frame in the holding frame 3, whereby the yoke I2 is securedto the pivot 23 by means of a screw 24. The opposite yoke 13 of thetension frame is built up in a similar manner as the yoke 12, i.e. itconsists also of a yoke bar I8 and two holding profiles I9 and 20 havingU-shaped cross-section. The saw-blades I4 are fastened here also on theinner legs of the holdingprofiles 19' and 20' by means of flats 22. Butwhilst the bar l8 and the profiles I9 and 20 of the yoke 12 are formedas a uniform static system since the outer legs of the holding profilesl9 and 20 border on the bar I8 free from play over their entire length,the outer legs of the holding profiles l9 and 20' lie without the bar 18with some play and are supported by two distance plates 25 arrangedsymmetrically to the longitudinal axis of the tension frame and thesectional plane IlI--III in FIG. 2, respectively, as indicated in FIG. 2for the one side. This constructive difference entails that due to thetension of the sawblades 14 the yoke 12 approximately bends according tothe line 26 shown in FIG. 2. The holding profiles I9 and 20' of the yoke13, which are supported only at the points 25 will approximately bendaccording to the line 26' in FIG. 2 due to the tension of the saw-bladesI4. Therefore, the deflections effected in the same sense compensateeach other extensively and guarantee a constant tension of all of thesaw-blades for the whole width of the set of the saw-blades.

On the side of the yoke 13 in the holding frame 3 straightening screws27 are provided which may be adjusted and screwed towards the lateralouter surfaces of the yoke bar 18' when the adjusting nut 28 is untied.Therefore, the yoke bar I8 is fixed in a predetermined position betweenthe straightening screws 27 tightened during the operation state,wherewith the whole tension frame is also secured in a predeterminedposition within the holding frame 3. Upon adjustment of the screws 27for exactly straightening the sawblades 14 parallel to the direction ofmovement of the frame 3 the tension frame 10 easily may be swivelledabout the pivot 23. In vertical direction the tension frame is securedwithin the holding frame 3 on the one hand by the screw 24 and on theother hand by safety hoops 29.

The staples of saw-blades 14 and holding flats 22, respectively, arepressed together and secured by fixing screws 30 accessible from thesides. These fixing screws are accessible through holes 31 of theholding frame 3 even if the tension frame is inserted as indicated inFIGS. 2 and 4.

For stretching the saw-blades 14 between the two yokes l2 and 13 theyoke 13 is movably arranged with respect to the legs 11. For thispurpose guiding bolts 32 are inserted in the ends of the legs 1 1,adjacent to the yoke 13, said guiding bolts traversing holes of the yokebar 18 and therewith guiding this yoke bar parallel to the longitudinaldirection of the legs 11. In the free part arranged between a leg I1 andan outer continuation of the yoke bar 18 at a time the bolts 32 areprovided with a thread on which a safety nut is set up. This nut borderson the shoulder of a joining piece of the yoke bar 18' at a time anddefines therewith the position of this bar and of the whole yoke,respectively, relative to the other parts of the tension frame. Thus,the tension of the saw-blades is transmitted through the yoke 13, thesafety nuts 33, and the bolts 32 to the legs 11 fixed to the yoke 12.

As shown in FIG. 5, in the region of the bolts 32 the yoke bar 18' has asubstantially greater height than the safety nut 33, so that accordingto FIG. 6 the U-shaped tension plate 34 of each cylinder body 35 may beinserted onto the shoulder of the outer joining piece of the yoke bar 18over the safety nut 33. The plate 34 is in connection with the actualcylinder body 35 by a cylindrical part having rectangular hole milled inaccordance with the shape of the yoke. Within the cylinder body there-isarranged the actual tension piston 36 having a pin-like joining piece 37extending practically coaxially to the bolt 32 when the tension cylinderis set on. Opposite to the tension piston36 there lies a pressure piston38 displaceahle by means of a screw 39 and a handle mountable thereto.The screw 39 is screwed with a further screw 40 acting to an auxiliarypiston 41 having a substantially smaller area than the pressure piston38.

For stretching the saw-blades according to FIG. two cylinder bodies areset on the two ends of the yoke bar 18. The large area pressure piston38 is moved now into the cylinder space by means of the screw 39,whereby the screw 40 turns along with and the auxiliary piston 41 runsbeforewith the same velocity. Therewith the tension piston 36 is movedfor-' ward with about the same velocity and pressed against the bolt 32by the pin-like joining piece 37. By further tightening the screw 39 inthe cylinder space a certain pressure and therewith a certain tensionforce may be created. Thus, the clearances existing at-first during themovement may be compensated by a rather quick movement of the tensionpiston 36. The final stretching is effected now by turning the screw 40within the screw 39 and by driving the small auxiliary piston 41,respectively, whereby the pressure within the cylinder space may beconsiderably increased again in order to attain the final pressure andtherewith the final tension in the sawblades. As soon as the pressure isattained in both the cylinders, which may. be indicated by manometers,the safety nuts 33 are screwed in as to snugly fitting the shoulders ofthe outer joining pieces of the yoke bar 18', so that after releasingand removing the tension cylinders the tension is maintained. Thisstretching is naturally effected when the tension frame is removed fromthe frame 3, whereby preferably at least two tension frames areassociated with a machine, which tension frames at will may be insertedin the machine and prepared apart from the same for later use therein,respectively.

Therewith the handling and function of the described reciprocating sawis extensively explained. After preparation of the machine, i.e. afterpiling up works 16 on the table and setting in a tension frame providedwith saw-blades the crank drive 8, 9 is started and moves the frames 3and 10 with the saw-blades to and fro above the table 15. Then the tableis lifted hydraulically upon a fixed pressure, so that the works 16 arelaid against the saw-blades from underneath upon a fixed pressure. Thensimultaneously grinding material is supplied through the pipe 17. Whenthe machining is finished the frame 3 with the frame 10 may be decoupledfrom the driving chariot 7 and moved completely to the left in FIG. I,so that the table 15 becomes accessible for replacing the works.

When the saw-blades are worn out the tension frame is removed by simplereleasing the screws 24, 27 and the safety hoops 29. Then a new preparedtension frame having a set of saw-blades may be inserted, straightenedby means of the screws 27, and then secured by means of the screw 24 andthe hoops 29.

What we claim is:

l. A reciprocating saw comprising in combination:

guide means;

a holding frame mounted on said guide means for linear reciprocatingmovement; I

a drive chariot hinged to said holding frame;

a set of saw blades and a saw-blade tension frame for carrying said sawblades, said saw-blades frame being removably mounted in said holdingframe with lateral clearance between said saw-blade and holding frames;

adjusting means for bringing said saw-blade frame in exact alginmentwith the direction of linear movement of said holding frame;

said saw-blade frame being adapted for engagement with a frame tensionunit when said frame is separated from said holding frame whereby tospan said saw-blades when said saw-blade frame is so removed.

2. A reciprocating saw according to claim 1, wherein the holdingprofiles of the one yoke and the outer legs of said profiles border onthe yoke bar free from play over their entire length, while the holdingprofiles of the other yoke are supported spaced from the associated yokebar in such a manner that the holding profiles of both the yokes mayundergo bending compensating each other by the tension effect of thesawblades.

3. A reciprocating saw according to claim 1, wherein the one yoke of thetension frame is pivotally connected to the legs of the tension frame inthe direction of the tension and in stretched position supported by anadjustable supporting means.

4. A reciprocating saw according to claim 3, including in combination isprovided a hydraulic tension unit, by means of which the tension frameis stretchable.

5. A reciprocating saw according to claim 4, wherein the tension unitincludes two cylinders, each of which is placeable between the one yokeend of the tension frame and the adjacent leg of the tension frame.

6. A reciprocating saw according to claim 4 wherein one yoke of saidtension frame is slidingly guided on bolts inserted in the ends of thelegs of said tension frame, an adjusting nut being arranged on athreaded portion of each of said bolts, said portion lying between theyoke end and the adjacent leg of said tension frame, said boltsprojecting from the ends of said yoke, and the yoke adjacent said bolthaving a shoulder formed thereon, and wherein said tension unitcomprises a cylinder body having means engageable with said shoulderportion of said yoke and with the exposed end of said bolts for applyingoppositely directed forces between said bolt end and said shoulder fortensioning said saw-blades, the relative spacing of said bolt ends andsaid shoulder being maintained by adjusting said nuts to thereby fix thesaid tension at a desired level.

7. A reciprocating saw according to claim 6, wherein the adjusting nutborders on the shoulder, on which the cylinder is placeable.

8. A reciprocating saw according to claim 7, wherein each of thecylinders has a pressure piston screwable by hand, said piston beingscrewed with a smaller pressure piston, whereby the final pressure andthe final tension, respectively, is attainable by actuating the smallerpressure piston.

9. A reciprocating saw according to claim 1 wherein said tension frameis pivotally supported at one end thereof in the ing a yoke bar with thelegs of said U-profiles extending forward of the said bar and projectingtoward each other to define flats bordering on the inner surfaces of thesaid legs, whereby said sawing blades extending between said yokes maybe fastened on said flats.

l k i i

1. A reciprocating saw comprising in combination: guide means; a holdingframe mounted on said guide means for linear reciprocating movement; adrive chariot hinged to said holding frame; a set of saw blades and asaw-blade tension frame for carrying said saw blades, said saw-bladesframe being removably mounted in said holding frame with lateralclearance between said sawblade and holding frames; adjusting means forbringing said saw-blade frame in exact alginment with the direction oflinear movement of said holding frame; said saw-blade frame beingadapted for engagement with a frame tension unit when said frame isseparated from said holding frame whereby to span said saw-blades whensaid saw-blade frame is so removed.
 2. A reciprocating saw according toclaim 1, wherein the holding profiles of the one yoke and the outer legsof said profiles border on the yoke bar free from play over their entirelength, while the holding profiles of the other yoke are supportedspaced from the associated yoke bar in such a manner that the holdingprofiles of both the yokes may undergo bending compensating each otherby the tension effect of the saw-blades.
 3. A reciprocating sawaccording to claim 1, wherein the one yoke of the tension frame ispivotally connected to the legs of the tension frame in the direction ofthe tension and in stretched position supported by an adjustablesupporting means.
 4. A reciprocating saw according to claim 3, includingin combination is provided a hydraulic tension unit, by means of whichthe tension frame is stretchable.
 5. A reciprocating saw according toclaim 4, wherein the tension unit includes two cylinders, each of whichis placeable between the one yoke end of the tension frame and theadjacent leg of the tension frame.
 6. A reciprocating saw according toclaim 4 wherein one yOke of said tension frame is slidingly guided onbolts inserted in the ends of the legs of said tension frame, anadjusting nut being arranged on a threaded portion of each of saidbolts, said portion lying between the yoke end and the adjacent leg ofsaid tension frame, said bolts projecting from the ends of said yoke,and the yoke adjacent said bolt having a shoulder formed thereon, andwherein said tension unit comprises a cylinder body having meansengageable with said shoulder portion of said yoke and with the exposedend of said bolts for applying oppositely directed forces between saidbolt end and said shoulder for tensioning said saw-blades, the relativespacing of said bolt ends and said shoulder being maintained byadjusting said nuts to thereby fix the said tension at a desired level.7. A reciprocating saw according to claim 6, wherein the adjusting nutborders on the shoulder, on which the cylinder is placeable.
 8. Areciprocating saw according to claim 7, wherein each of the cylindershas a pressure piston screwable by hand, said piston being screwed witha smaller pressure piston, whereby the final pressure and the finaltension, respectively, is attainable by actuating the smaller pressurepiston.
 9. A reciprocating saw according to claim 1 wherein said tensionframe is pivotally supported at one end thereof in the holding frame,and wherein adjusting screws bear against the lateral edges of saidframe toward the opposite end thereof to fix the position of the saidtension frame within said holding frame.
 10. A reciprocating sawaccording to claim 1 wherein said saw-blade frame comprises a pair ofopposed yokes, each yoke having removably screwed U-shaped holdingprofiles enclosing a yoke bar with the legs of said U-profiles extendingforward of the said bar and projecting toward each other to define flatsbordering on the inner surfaces of the said legs, whereby said sawingblades extending between said yokes may be fastened on said flats.